# Finding how much a 5 cm pad compresses when an egg hits it

## Homework Statement

A 56.0 g egg falls 120.0 m from rest and hits a 5.00 cm thick foam pad. The egg does not break, but instead compresses the foam pad. It is 6.25 ms from the moment the egg hits the foam ad until all downward motion (falling) is stopped. Assuming there is a constant upward acceleration due to the compressing of the foam pad, how much is the pad compressed?

m= 56.0 g; delta y= 12 m; pad= 5.00 cm; delta t= 6.25 ms; a= -9.81 m/s2

## Homework Equations

m1v1,i+m2v2,i=m1v1,f + m2v2,f; KE= 1/2mv2; F(delta t)= delta P

I really have no idea what to do in this case, and I need to get this equation done. It's the last one on my set. Please help!

Related Introductory Physics Homework Help News on Phys.org
rock.freak667
Homework Helper
You could try using conservation of energy to get the speed of the egg at the moment of impact and then use that to get the acceleration of the egg.

You just made my life so much easier! Thank you!

gneill
Mentor
You just made my life so much easier! Thank you!
Are you sure that your problem statement contains all the relevant information? Perhaps the value of the upward acceleration due to the foam pad is missing?

cepheid
Staff Emeritus
Gold Member
Are you sure that your problem statement contains all the relevant information? Perhaps the value of the upward acceleration due to the foam pad is missing?
Nope. This information is not required. Here's a hint: the deceleration time is given, and a constant force is assumed.

To the original poster: is it 120.0 m or 12 m? You've written both of these in two different places. The latter gives me an answer that works. The former does not (i.e. the pad will not be thick enough).

gneill
Mentor
Nope. This information is not required. Here's a hint: the deceleration time is given, and a constant force is assumed.
Ah yes. How late-night-fuzzy-headed of me. Thanks.